1. Field of the Invention
This invention relates to a master cylinder of the "quick-fill" type, primarily for use in a vehicle braking system. Such a master cylinder is one which, when actuated, initially expells a large quantity of fluid into the braking system to cause rapid take-up of brake clearances and thereby minimize the amount of brake pedal travel required for this purpose. Examples of quick-fill master cylinders are described in our published co-pending British Pat. application No. 2074675.
2. Description of the Prior Art
There is an increasing trend in modern vehicle braking systems to use fabricated master cylinders in which the pressure cylinder is a simple steel tube of relatively thin uniform wall thickness, with a separate reservoir, usually of plastics material, mounted on the cylinder and communicating with the interior of the latter through transverse ports formed in the cylinder wall. The provision of a quick-fill facility in a master cylinder of this kind gives rise to considerable problems because a large chamber has to be provided for the low pressure quick-fill fluid, and, valve means is also required to control communication between this chamber and the reservoir. Because of the nature of the pressure cylinder there is insufficient material available to enable previous proposals for incorporating the valve means in the structure of the cylinder to be practicable.